Process for the manufacture of asphalt



Patented Oct. 11, 1932 UNITED STATES PATENT OFFICE ALBERT LOEBEL, FAMSTERDAM, NETHERLANDS, ASSIGNOR T0 DE BATAAIFSCHE PETROLEUMMAATSCHAPPIJ', OF THE HAGUE, NETHERLANDS PROCESS FOR THE MANUFACTURE OFASPHALT N0 Drawing. Application filed February 14, 1929, Serial No.340,006, and in the Netherlands December 9, 1927.

It is known that crude asphaltic oil, after any gasolene, kerosene andgasoil contained therein have been removed by distillation, yields onfurther distillation a residue which,

depending on the extent to which the distillation is carried out,represents a more or less hard asphalt.

For practical purposes, asphalt should comply with various requirementswhich difi'er according to the purpose for which it is used. From adefinite crude oil, only one and the same quality of asphalt may beobtained by distillation, which can only be modified slightly byaltering the conditions under which the distillation takes place.

Also, with the aid of oxidizing treatments (the well-known blowing ofasphalt), it is only possible to alter the quality of the asphaltgradually.

I have found, however, that the quality of the final product to beobtained from an 1 oil may be highly improved by adding thereto, at anystage of the distillation (if desired, even to the starting material, i.e., the

crude oil), at least 20% or more of hydrocarbons which are soluble inliquid S0 and my invention, broadly speaking, relates to such process.This material is obtained by extraction with liquid sulphur dioxide at a.low temperature of liquid hydrocarbons with an initial boiling point ofat least 250 C. The resulting extracts are mainly of an unsaturatedcharacter (aromatics are here taken also as unsaturated hydrocarbons).

If, according to my invention, an oil to which the said material isadded, is subjected to a distillation with steam, a final product isobtained which is very tough in comparison with the product obtainedfrom the same oil and under the same circumstances but without theaddition of at least 20% of sO -soluble hydrocarbons.

Thus, if an oil yields, on distillation, a final product which isinsufliciently tough or duc- 4 tilewhich, according to hitherto-knownmethods, may be only improved to a certain extent by admixing otherasphalts after distillation--I may add to that oil the abovementionedmaterial and then apply a distillation treatment with steam to themixture in order toobtain an improved product.

If, according to my invention, an oil to which the said material isadded, is subjected to an oxidizing distillation process, a finalproduct is obtained which is very hardin com parison with the productobtained from the same oil and under the same circumstances but withoutthe addition of at least 20 per cent of SO -soluble hydrocarbons. Thus,if an oil yields, on oxidizing distillation, a final product which isinsufficiently hard, I may add to that oil the above-mentioned materialand then apply an oxidizing distillation treatment to the mixture inorder to obtain an improved product. When speaking in the above of atough or ductile asphalt, I means that the consistency of such asphaltis sensitive to changes in temperature; that is to say, in terms wellunderstood by those skilled in the art, its penetration curve is steep.

When speaking of a hard asphalt, I mean that its penetration curve israther flat.

The following table contains some results obtained when applying myinvention to Venezuelan residue:

Steam asphalt Blown asphalt With the addition of 30 per cent SO solublehydrocarbons Without addition Melting point 128 C. Penetration at 0 C 64 a penetration curve steeper than that of an asphalt obtained withoutthe addition of the hydrocarbons. c

In'testimony whereof I have ailixed my signature.

ALBERT LOEBEL.

an initial boiling point of at least 250 Ct,

and thereafter distilling the mixture in the presence of air to obtainan asphalt having a penetration curve flatter than that of an asphaltobtained without the addition of the hydrocarbon oil.

2. A process of manufacturing asphalt from crude asphaltic oil orasphaltic petroleum residues, comprising the steps of adding to theinitial material a hydrocarbon oil extracted with liquid sulphur dioxidefrom petroleum distillates of the initial material and which hydrocarbonoil has an initial boiling point of at least 250 (3., and-thereafterdistilling the mixture to produce an asphalt.

3. A process of manufacturing asphalt from crude asphaltic oil orasphaltic petroleum residues, comprising the steps of adding to theinitial material at least 20% of extracted hydrocarbons soluble inliquid sulphur dioxide and having aninitial boiling point of at least250 C., and thereafter distilling the mixture with steam to obtain anasphalt which is more ductile and which has a penetration curve steeperthan that of an asphalt obtained without the addition of thehydrocarbons.

4. A process of manufacturing asphalt from crude asphaltic oil orasphaltic petroleum residues, comprising the steps of adding to theinitial material at least 20% of hydrocarbons, the total addedhydrocarbons being substantially entirely soluble in liquid sulphurdioxide and having an initial boiling point of at least 250 C., andthereafter distilling the mixture with steam to obtain an asphalt whichis more ductile and which has

